The Wyatt Lab researchers studying the gps2 mutant genome have identified a gene that appears to play a significant role in plant signal transduction. The candidate gene was identified through deep sequencing of the gps2 mutant genome and then comparing the results to the wild type (WT) genome. The analysis revealed a difference of a single gene in one area of the genome associated with plant signaling which had been disrupted by a semi-random T-DNA insertion that silenced (or shut off) the gene in the mutant. In the WT genome, the gps2 gene is intact and expresses normally during GPS treatment.
Figure 1 – WT GPS treatment response (shown below as Ws) compared to other gps mutants.
To determine if the silenced gps2 gene is indeed the one responsible for the differences between mutant and WT plants responding to GPS treatment, the team is now testing seed stock1 with the gps2 candidate gene silenced for homozygosity. Once they have verified and grown homozygous plants (meaning both copies of the gps2 gene – one on each allele of the chromosome – are knocked out), the team will subject the plants to GPS treatment. If the test plants bend the opposite direction of WT control plants, the researchers will have found their gene.
Figure 2 – Chromosome with different copies of the candidate gene on matching alleles.
Figure 3 – Homozygous chromosome with exact copies of the candidate gene on matching alleles.
1Fortunately for scientists studying Arabidopsis plants there are now global not-for-profit organizations providing research support (such as, information and seed clearinghouses). When the Wyatt Lab team identified their candidate gene and needed a WT seed stock with just that single gene disrupted, they only had to open a browser and search an online database to locate homozygous seeds. In the past, this would have provided a formidable challenge for researchers and significantly slowed their ability to tests their hypotheses.